The Sea of Galilee is a holy site to Christians. The Bible says it is where Jesus walked on water.

The FBI investigation did not result in any "formal allegations of wrongdoing," according to the Politico report. Politico said House Majority Leader Eric Cantor, the senior lawmaker on the fact-finding trip, was "so upset by the antics that he rebuked the 30 lawmakers" on Aug. 19, 2011, the day after the incident.
From Yoder's statement to Politico:

A year ago my wife, Brooke, and I joined colleagues for dinner at the Sea of Galilee in Israel. After dinner I followed some members of Congress in a spontaneous and very brief dive into the sea and regrettably I jumped into the water without a swimsuit. It is my greatest honor to represent the people of Kansas in Congress and (for) any embarrassment I have caused for my colleagues and constituents, I apologize.

Cantor's chief of staff, Doug Heye, said in a statement to Politico and CNN that the House majority leader "dealt with this immediately and effectively to ensure such activities would not take place in the future."

Tiffany Quayle, the wife of Arizona GOP Rep. Ben Quayle, told CNN in a statement that she and her husband were on the trip but they "were neither party nor witness to any of the inappropriate behavior" described in the Politico article.

The Politico story also named Republican Reps. Steve Southerland of Florida, Tom Reed of New York, Jeff Denham of California and Michael Grimm of New York as taking part in the swimming, although Yoder was the only one who was said to be naked.